Mysterious power surges damage BART system

SAN FRANCISCO - Bay Area commuters faced overcrowded trains, travel delays and other inconveniences for the second time in two weeks on Thursday due to a mysterious electrical problem affecting the region's rail transit system.

Bay Area Rapid Transit officials said 50 of their train cars - twice as many as originally estimated - were damaged by unexplained power surges on Wednesday.

Another 80 BART cars were taken out the voltage spikes at the beginning of the month, but in a different segment of the system.

System spokeswoman Alicia Trost said BART engineers have not been able to determine what's causing the problem and outside experts are being flown in to evaluate.

"What's occurring is that when a train is traveling over that section of track, it experiences a high spike in voltage and that is damaging a piece of the propulsion equipment on the train car," Trost said.

The electrical surges are burning out critical components and putting cars that typically carry over 200 passengers apiece during peak commute hours out of commission. That has made BART trains even more crowded than usual and left some people waiting on station platforms.

System officials said the electrical problems don't pose a danger to passengers.

The short section of track 36 miles west of downtown San Francisco where the latest surges happened remained shut down Thursday to avoid any damage to other cars, Trost said.

"We already have a limited number of cars in our fleet," she said.